On a ride at over 70 degrees F in the spring, passing through a Baltimore suburb, I saw a rider in tights and long sleeves ahead of me. I guessed that anyone with that much winter cycling clothing on on a warm morning had to be European or South American, probably a current or former pro. Up close, I saw that he was heavily tanned (check), fairly compact of build (check), and wearing expensive-looking (i.e., genuine) team clothing, including Castelli tights with a huge embroidered Castelli logo on each thigh (check and mate).
Final proof of pro status: when I passed, he glanced at me but didn't bother speeding up even the tiniest bit.